Whereas the iPhone 5S is set to be an incremental update focusing on new features and software the iPhone 6 is set to be a completely new handset. This week a patent has been discovered which suggest that the model may be the first ever smartphone to be made from the new Liquidmetal material. The patent has been filed by Crucible Intellectual Properties and it is a joint venture between American manufacturer Apple and Liquidmetal Technologies. The two companies actually agreed a licensing agreement way back in 2010 but since then very little has been heard about their plans until this new patent came to light. It would suggest that Apple will be the first company to release a phone featuring this material which is a combination of different alloys that together have a similar atomic composition to glass.
The new iPhone 6 will not only benefit from eye catching looks if this new material is used but it will also have a number of benefits to the user. Liquidmetal is incredibly durable and is also resistant to corrosion. From a manufacturer's point of view the material is also very malleable which makes it ideal for use on a smartphone device. There are concerns however over producing large amounts of the material as the stretching process that is used can weaken its durability. The new patent that has been filed however does highlight how the correct amounts can be produced and stretched without it suffering from any weaknesses. The development of this material has come too late for it to feature on the iPhone 5S which is set to launch this quarter but the iPhone 6 is a realistic handset where we could see its use implemented for the first time.
Liquidmetal is an amorphous alloy that is revolutionising modern manufacturing. This alloy uniquely combines the strength of forging with intricate moulding capabilities superior to MIM (metal injection moulding). Twice the strength of titanium, delivers repeatable moulded features within /-50um and ultralow shrinkage rate of 0.2%. In conventional Metal Injection Moulding (MIM) processes, the MIM sintering step typically shrinks the “green state” part by 15-20% which can cause warping and requires secondary machining to meet precision tolerances.
In addition to precision net-shape moulding, an as-moulded Liquidmetal part typically has a surface roughness of less than 0.05um. This is a significant benefit compared with other processes that require additional processing to meet a surface spec of this quality. Diecast alloys and MIM components typically have surface roughness values that range from 0.8 to 1.6um. Liquidmetal’s atomic structure allows incredibly precise replication of tool surfaces, allowing very fine details, textures or highly polished surfaces to be imparted in a single step during high rate production.
Liquidmetal Alloy is stronger than high-strength titanium, with a yield strength of 1900Mpa. High-strength titanium (Ti-6Al-4V) has a yield strength of 830 Mpa (120 ksi) and an ultimate tensile strength of only 900Mpa. Like most glasses, the yield strength of Liquidmetal Alloy is nearly identical to its ultimate tensile strength, meaning that when the material is stressed to its yield limit, rather than plastically deforming, it will break, and is therefore technically considered brittle, even though it is highly elastic (see below).
The exceptional strength of Liquidmetal is more remarkable when compared with other metal moulding or casting processes. The ultimate tensile strength of die cast materials (zinc, aluminum, and magnesium) does not exceed 425Mpa, and one of the strongest MIM materials (MIM 4605 HT) has an ultimate strength of 1650Mpa.
Liquidmetal also has a very high hardness which can prove beneficial for parts that require a durable scratch and wear resistant surface. The hardness value of LM001B is 550 Vickers (52 HRC), which is significantly harder than conventional metal alloys. Die cast alloys can achieve a hardness of 130 Vickers, Titanium (Ti-6Al-4V) can reach 340 Vickers (34 HRC), and Stainless Steel (17-4 PH) can reach 325 Vickers (33 HRC).
While Liquidmetal alloy may be more brittle than some high strength materials, LM001B can undergo 2.0% of elongation before reaching its yield point. This is driven by the material’s Elastic Modulus, which is 93GPa, and its unique amorphous atomic structure. Other high strength materials tend to be much stiffer, reflecting their higher modulus of elasticity. Only Liquidmetal alloy can provide this unique combination of high strength and elasticity.
LM001B performs very well with no corrosion evident during a salt spray test conforming to ASTM standard B-117 for over 336 hours. This test was performed on an as-moulded surface on the part.